| 摘要 |
PURPOSE:To implement frequency scanning over a wide range in a short time by eliminating a gap of the scanning frequency while a change in an output light intensity is small according to a specific condition. CONSTITUTION:The apparatus consists of a microprocessor 11, a D/A converter 12, a D/A converter 13, a semiconductor laser drive circuit 14, a semiconductor laser 15, a temperature control circuit 16 and a constant temperature oven 17. Then the temperature T of the semiconductor laser is expressed in equation I with a temperature To for scanning start, a temperature change Ts, and an integral number (n), and the current scanning range in this case is expressed in equation II with a minimum value Io for the current scanning range at n=0, a change Is in the current scanning range attended with the temperature change, and a current scanning width Iw. Moreover, when the temperature change Ts, the change Is in the current scanning range attended with the temperature change, and the current scanning width Iw satisfy equation III, the output light intensity change is less and the gap of the scanning frequencies is small. Thus, broad range optical frequency scanning is attained by scanning the temperature and the current and the scanning of the current is repeated by changing the temperature at a prescribed range. Thus, the optical frequency is scanned in a short time. |
